Date: Wed, 11 Aug 2010 08:39:37 -0400
From: Don Zickus <dzickus@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Robert Richter <robert.richter@amd.com>,
        Cyrill Gorcunov <gorcunov@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>, Lin Ming <ming.m.lin@intel.com>,
        Ingo Molnar <mingo@elte.hu>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Huang, Ying" <ying.huang@intel.com>, Yinghai Lu <yinghai@kernel.org>,
        Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH] perf, x86: try to handle unknown nmis with running
 perfctrs
Message-ID: <20100811123937.GB4879@redhat.com>
References: <20100804161046.GC5130@lenovo>
 <20100804162026.GU3353@redhat.com>
 <20100804163930.GE5130@lenovo>
 <20100804184806.GL26154@erda.amd.com>
 <20100804192634.GG5130@lenovo>
 <20100806065203.GR26154@erda.amd.com>
 <20100806142131.GA1874@redhat.com>
 <20100809194829.GB26154@erda.amd.com>
 <20100810204856.GA16571@redhat.com>
 <20100811024451.GA26835@nowhere>
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On Wed, Aug 11, 2010 at 04:44:55AM +0200, Frederic Weisbecker wrote:
> May be make it just a pending bit. I mean not something that can
> go further 1, because you can't have more than 1 pending anyway. I don't
> know how that could happen you get accidental perctr_skip > 1, may be
> expected pending NMIs that don't happen somehow, but better be paranoid with
> that, as it's about trying not to miss hardware errors.

I guess I was thinking about the SMI case where it drains the perfctr(s)
and then retriggers them but I guess even in that case the most you can
have is one extra NMI.  So yeah, you are probably right, I should have
used a flag instead of incrementing.

Cheers,
Don
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